physical science ch.9-13 vocabulary

Chapter 9

Atom

• The smallest particle of an element that can enter into a chemical combination

Electrons

• Negatively charged subatomic particles

Quantum

• A discrete amount

Quantum Mechanics

• The branch of physics that replaced the classical-mechanical view (that everything moved according to exact laws of nature) with the concept of probability

Photoelectric effect

• The emission of electrons that occurs when certain metals are exposed to light

Photon

• A “particle” of electromagnetic energy

Dual nature of light

• Light sometimes behaves as waves and sometimes as particles

Line emission spectrum

• A set of bright spectral lines of certain frequencies or wavelengths formed by dispersion of light from a gas discharge tube.

Line absorption spectrum

• A set of dark spectral lines of certain frequencies or wavelengths, formed by dispersion of light that has come from an incandescent source and has then passed through a sample of cool gas

Principal quantum number

• The numbers n = 1, 2 ,3,…used to designate the various principal energy levels that an electron may occupy in an atom

Ground state

• The lowest energy level of an atom

Excited states

• The energy levels above the ground state in an atom

Fluorescence

• The property of a substance, such as the mineral fluorite, of producing visible light while it is being acted upon by ultraviolet light

Phosphorescence

• A glow of light that persists after the removal of the source of photons needed for excitation of the material’s electrons

X-rays

• High-frequency, high-energy, electromagnetic radiation formed when high-speed electrons strike a metallic target

Laser

• An acronym for Light Amplification by Stimulated Emission of Radiation

• It is coherent, monochromatic light

Stimulated emission

• Process in which an excited atom is caused to emit a photon

Heisenberg’s Uncertainty principle

• It is impossible to know simultaneously the exact velocity and position of a particle

Matter (de Broglie) waves

• The waves produced by moving particles

Chapter 10

Nucleus

• The central core of an atom• Composed of protons and neutrons

Protons

• Positively charged particles in the nuclei of atoms

Neutrons

• Neutral particles found in the nuclei of atoms

Nucleons

• A collective term for neutrons and protons (particles in the nucleus)

Atomic number

• Symbolized Z, it is equal to the number of protons in the nucleus of an atom of that element

Element

• A substance in which all the atoms have the same number of protons - the same atomic number

Neutron number

• The number of neutrons in the nucleus of an atom

Mass number

• The number of protons plus the number of neutrons in a nucleus

• The total number of necleons

Isotopes

• Forms of atoms of an element that have the same numbers of protons but differ in their numbers of neutrons

Atomic mass

• The average mass of an atom of the element in naturally occurring samples

Strong nuclear force

• The short-range force of attraction that acts between two nucleons and holds the nucleus together

Radioactive isotope

• An isotope that undergoes spontaneous decay

Radioactivity

• The spontaneous process of a sample of a radionuclide undergoing a change by the emission of particles or rays

Alpha decay

• The disintegration of a nucleus into a nucleus of another element, with the emission of an alpha particle

Beta decay

• The disintegration of a nucleus into a nucleus of another element, with the emission of a beta particle

Gamma decay

• An event in which a nucleus emits a gamma ray and becomes a less energetic form of the same nucleus

Half-life

• The time it takes for half the nuclei in a sample of a given radionuclide to decay

Carbon-14 dating

• A procedure used to establish the age of ancient organic remains by measuring the concentration of 14C and comparing it to that of present-day organic remains

Fission

• A process in which a large nucleus is split into two intermediate-size nuclei, with the emission of neutrons and the conversion of mass into energy

Chain reaction

• Occurs when each fission event causes at least one more fission event

Critical mass

• The minimum amount of fissionable material necessary to sustain a chain reaction

Fusion

• A process in which a smaller nuclei are fused to form larger ones, with the release of energy

Plasma

• A high-temperature gas of electrons and protons or other nuclei

Mass defect

• Any decrease in mass during a nuclear reaction

Chapter 11

Chemistry

• The division of physical science that studies the composition and structure of matter and the reactions by which substances are changed into other substances

Compound

• A substance composed of two or more elements chemically combined in a definite, fixed proportion by mass

Mixture

• A type of matter composed of varying proportions of two or more substances that are just physically mixed, not chemically combined

Solution

• A mixture that is uniform throughout• A homogeneous mixture

Unsaturated solution

• A solution in which more solute can be dissolved at the same temperature

Saturated solution

• A solution that has the maximum amount of solute dissolved in the solvent at a given temperature

Solubility

• The amount of solute that will dissolve in a specified volume or mass of solvent (at a given temperature) to produce a saturated solution

Supersaturated solution

• A solution that contains more than the normal maximum amount of dissolved solute at a given temperature and hence is unstable

Molecule

• An electrically neutral particle composed of two or more atoms chemically combined

Allotropes

• Two or more forms of the same element that have different bonding structures in the same physical phase

Period

• In physics, the time for a complete cycle of motion. In chemistry, one of the seven horizontal rows of the periodic table

Periodic law

• The properties of elements are periodic functions of their atomic numbers

Groups

• The vertical columns in the periodic table

Representative elements

• The A group elements in the periodic table

Transition elements

• The B group of elements in the periodic table

Inner transition elements

• The lanthanides and actinides, the two rows at the bottom of the periodic table, make up the inner transition elements

Metal

• An element whose atoms tend to lose valence electrons during chemical reactions

Nonmetal

• An element whose atoms tend to gain (or share) valence electrons during chemical reactions

Electron configuration

• The order of electrons in the energy levels of an atom

Valence shell

• An atom’s outer shell, which contains the valence electrons

Valence Electrons

• The electrons that are involved in bond formation, usually those in an atom’s outer shell

Ionization energy

• The amount of energy it takes to remove an electron from an atom

Ion

• An atom, or chemical combination of atoms, that has a net electric charge

Noble gases

• The element of Group 8A of the periodic table• He, Ne, Ar, Kr, Xe, Rn

Alkali metals

• The elements in Group 1A of the periodic table

• Li, Na, K, Rb, Cs, Fr

Halogens

• The elements in Group 7A of the periodic table

• F, Cl, Br, I, At

Alkaline Earth metals

• The elements in Group 2A of the periodic table

• Be, Mg, Ca, Sr, Ba, Ra

Chapter 12

Law of conservation of Mass

• No detectable change in the total mass occurs during a chemical reaction

Formula Mass

• The sum of the atomic masses of the atoms showing in the chemical formula of the compound or element

Law of definite proportions

• Different samples of a pure compound always contains the same elements in the same proportion by mass

Limiting reactant

• A starting material that is used up completely in a chemical reaction

Excess reactant

• A starting material that is only partially used up in a chemical reaction

Octet rule

• In forming compounds, atoms tend to gain, lose, or share electrons to achieve electron configurations of the noble gases

Ionic compounds

• Compounds formed by an electron transfer process in which one or more atoms lose electrons and one or more other atoms gain them to form ions

Lewis symbol

• The element’s symbol represents the nucleus and inner electrons of an atom, and the valence electrons are shown as dots arranged around the symbol

Lewis Structures

• “electron dot” symbols used to show valence electrons in molecules and ions of combounds

Cations

• Positive ions; so called because they move toward the cathode (the negative electrode) of an electrochemical cell

Anions

• Negative ions; so called because they move toward the anode (the positive electrode) of an electrochemical cell

Ionic bonds

• Electrical forces that hold the ions together in the crystal lattice of an ionic compound

Stock system

• A system of nomenclature for compounds of metals that form more than one ion

• A roman numeral placed in parentheses directly after the name of the metal denotes its ionic charge in the compound being named

Covalent compounds

• Those in which the atoms share pairs of electrons to form molecules

Covalent bond

• The force of attraction caused by a pair of electrons to form molecules

Polar Covalent Bond

• One in which the pair of bonding electrons is unequally shared, leading to the bond’s having a slightly positive end and a slightly negative end

Electronegativity

• A measure of the ability of an atom to attract shared electrons to itself

Polar molecule

• A molecule that has a positive end and a negative end – that is, one that has a dipole

Hydrogen bond

• The dipole-dipole forces between a hydrogen atom in one molecule and a nearby oxygen, nitrogen, or fluorine atom in the same or a neighboring molecule

Chapter 13

Chemical properties

• Characteristics that describe the chemical reactivity of a substance – that is, its ability to transform into another substance

Chemical reaction

• A change that alters the chemical composition of a substance

Reactants

• The original substances in a chemical reaction

Products

• The substances formed during a chemical reaction

Combination reaction

• One in which at least two reactants combine to form just one product

• A+B > AB

Decomposition reactions

• One in which only one reactant is present and breaks into two (or more) products: AB > A + B

Exothermic reactions

• A reaction that has a net release of energy to the surroundings

Endothermic reactions

• A reaction that absorbs energy from the surroundings

Activation energy

• The energy necessary to start a chemical reaction

• A measure of the minimum kinetic energy that colliding molecules must possess in order to react

Acid-carbonate reaction

• An acid and a carbonate (or hydrogen carbonate) react to give carbon dioxide, water, and a salt

Combustion reaction

• The reaction of a substance with oxygen to form an oxide, along with heat and light in the form of fire

Catalyst

• A substance that increases the rate of reaction but is not itself consumed in the reaction

Acid

• A substance that gives hydrogen ions (or hydronium ions) in water

Equilibrium

• In chemistry, a dynamic process in which the reactants are combining to form the products at the same rate at which the products are combining to form the reactants

Base

• A substance that produces hydroxide ions in water

pH

• A measure (on a logarithmic scale) of the hydrogen ion (or hydronium ion) concentration in a solution

Acid-base reaction

• The H+ of the acid unites with the OH- of the base to form water, while the cation of the base combines with the anion of the acid to form a salt

Salt

• An ionic compound that contains any cation except H+ combined with any anion except OH-

Double-replacement reactions

• Reactions that take the form of AB + CD > AD + CB

• The positive and negative components of the two compounds “change partners”

Precipitate

• An insoluble solid that appears when two clear liquids (usually aqueous solutions) are mixed

Oxidation

• Occurs when oxygen combines with another substance (or when an atom or ion loses electrons)

Reduction

• Occurs when oxygen is removed from a compound (or when an atom or ion gains electrons)

Activity series

• A list of elements in order of relative ability to of their atoms to be oxidized in solution

Single-replacement reaction

• Reactions in which one element replaces another that is in a compound

• A + BC > B + AC

Mole (mol)

• The quantity of a substance that contains 6.02 x 1023 formula units (the number of atoms in exactly 12 g of carbon-12)

Avogadro’s number

• 6.02 x 1023, symbolized NA; the number of entities in a mole.

Molarity (M)

• A measure of solution concentration in terms of moles of solute per liter of solution